Generally, an image forming apparatus receives an image signal and transfers the image signal onto a sheet of paper to form a visible image. In particular, an image forming apparatus having a scanning function, such as a facsimile or a scanner, scans an image recorded on a document, converts the image into digital image information, which may be reproduced on a sheet of paper or a display. The image forming apparatus with the scanning function includes a scanning unit scanning an image cm a document and an automatic document feeding (ADF) unit feeding each page of the document to the scanning unit.